When it is worth changing
- When you move in, whether you bought or rent: you have no idea how many keys are out there.
- If your keys are lost or stolen, especially if something on the keyring points to your address.
- After an attempted break-in: even if the door still opens, the cylinder may be damaged.
- If the key sticks or only turns sometimes. Try a dry lubricant (graphite or PTFE) first; oil collects dust and makes it worse.
Cylinder or whole lock?
The lock (cerradura) is the mechanism inside the door that moves the latch and bolts. The cylinder (bombín or cilindro) is just the part you put the key into. If the lock works and your worry is keys or security, changing the cylinder is enough: quicker, cheaper and no work on the door itself.
The whole lock needs replacing if the mechanism inside is broken, if the bolt sticks even when the key turns, or if the lock doesn’t take a standard-profile cylinder.
Measuring it and choosing a secure one
Open the door and look at its edge: a long screw holds the cylinder in place. Measure from the centre of that screw to each end of the cylinder. You get two numbers, for example 30x40, and the new one should match: a cylinder that sticks out past the outside plate is easier to snap. Armoured doors often need a longer or asymmetric cylinder, with one side longer than the other.
- Anti-bumping and anti-pick (anti-ganzúa): make it harder to open without force.
- Anti-snap (anti-extracción or anti-rotura): designed so it can’t be pulled out whole if someone breaks it.
- Ownership card (tarjeta de propiedad): copies of the key are only cut on showing the card.
- Security plate (escudo): covers the cylinder on the outside against blows and drilling.
- The UNE-EN 1303 standard rates cylinders by resistance; if the maker states it, use it to compare.
Changing a standard cylinder step by step
- Work with the door open, and check the new cylinder has the same measurements.
- Undo the fixing screw on the edge of the door and keep it.
- Put the key in and turn it slightly, roughly a quarter turn or less, until the cam (leva, the tab in the middle) lines up with the body of the cylinder.
- Pull on the key: the cylinder slides out with it. If it doesn’t, turn a little more until the cam stops catching.
- Slide the new one in with the cam in the same position, refit the screw and test the key several times from both sides before you close the door.
Armoured doors (puerta blindada or acorazada)
Many armoured doors have multi-point locks (cerradura multipunto) that shoot several bolts at once, and some use special-profile cylinders or lever locks (llave de gorjas) that come out differently. Get it wrong and the door may not lock properly, or not open at all.
So on an armoured door, changing the cylinder is a job for a locksmith professional, who can also tell you whether the lock takes a higher-security cylinder and plate.
What it costs, renting, and calling us
There is no single price. It depends on the security level of the cylinder, its size (long and asymmetric ones cost more), whether you add a security plate, the type of door and how urgent it is: a booked visit is not the same as an immediate call-out.
If you rent, tell your landlord in writing first and keep the old cylinder; many landlords will ask for a copy of the new key. Who pays depends on why it is being changed; see Who pays for repairs?. Send us a photo of the cylinder from outside and one of the door edge and we’ll quote in English with no obligation, or call 608 525 847.
Locked out? Don’t try to take the cylinder apart from the landing: call a locksmith professional.